'easily agree' is correct and usable in written English.
You can use it when you want to express that something was agreed to with little effort or difficulty. For example: "We easily agreed on the details of the contract."
Why does she so easily agree to go back?
We no longer easily agree on what it means to be good, or principled, or brave.
This isn't a book you can easily agree with and in a way that's the point.
Some administration officials and Republican lawmakers suggested they could easily agree on that issue, perhaps leading to a wider accord.
According to the company's website, the show illustrates that normality is relative, something New Yorkers can easily agree with.
Even so, the remaining costs for business tax breaks, especially for struggling small businesses, outstrip the sources of revenues that Democrats can easily agree to.
"The Medicare adjustments will be easily agreed to," Mr. Armey said.
"Yes, we're a racist organization," he easily agrees of his movement, whose adherents lately have been pasting provocative stickers in Seattle, Cincinnati and other places suffering racial tensions.
It is, however, one of those recommendations that reads well on paper and is easily agreed to, but which will be fought over bitterly in legislation.
Soufan realized that the prisoner was trained in counter-interrogation techniques, since he easily agreed to things that Soufan already knew — that he had fought in Bosnia, Somalia, and Afghanistan, for instance — and denied everything else.
If something is too easy, people start to wonder why that was the case and what might be wrong with the deal they have just (so easily) agreed to.
